1. Field of the Invention
The invention is concerned with improving the load carrying ability of a lubricant and with compositions containing same. In particular, the additive is a diorganophosphorus derivative of urethane.
2. Discussion of the Prior Art
It is known that sliding or rubbing metal or other solid surfaces are subject to wear under conditions of extreme pressure. Wearing is especially acute in modern engines in which high temperatures and contact pressures are present. Under such conditions, severe erosion of metal surfaces can take place even with the newer lubricants, in the absence of load carrying additives.
Certain phosphorus compounds are known for use as load bearing additives. For example, U.S. Pat. No. 3,591,501 discloses the use of a hydroxy-organophosphine oxide. U.S. Pat. No. 3,583,915 teaches the use of a di(organo)hydrogen phosphonate to impart load carrying properties to a lubricant. No patent, or other reference, is known, however, that teaches or suggests the compounds disclosed herein as load carrying additives.